Astronomers report startling find on planet formation

SANTIAGO (AFP) - Astronomers are reporting a find that challenges traditional theories as to how rocky planets - such as Earth - are formed.

Besides Earth, our solar system has three other rocky planets: Mercury, Venus and Mars. They have a solid surface and core of heavy metals, and differ from planets that are large spinning bodies of gas, like Jupiter or Saturn.

The new findings suggest rocky planets may be even more common in the universe than previously thought. The research was presented Friday in the Astrophysical Journal of Letters.

The astronomers used a cutting-edge telescope called ALMA, on a mountaintop 5,000 m high in the remote desert of northern Chile.